1. Field of the Invention
This invention relates to novel p-menthane sulfonates and their use as hydrotropes in aqueous compositions.
2. The Prior Art
Many aqueous compositions contain organic components of poor water solubility. Hydrotropes are formulated into these liquids to increase the aqueous solubility of the hydrophobic organic components. Commonly employed hydrotropes include the salts of toluene, xylene or cumene sulfonates. While these commercial compounds perform satisfactorily, there is a need for lower cost alternatives, especially materials not derived from petrochemical feedstocks.
Among the relatively low-cost renewable raw materials is turpentine, an extract of pine trees. The .alpha. and .beta.-pinenes, which are major components of turpentine, when reacted with pyrosulphuryl chloride yield sulfonate compounds as in U.S. Pat. No. 2,220,678. Traynor et al, J. Org. Chem., Vol. 44, 1557, 1979, reports that sodium p-menth-6-ene-2-sulfonate (I) can be formed from the dehydration of the reaction product between sodium sulfite and the .alpha.-pinene derivative limonene oxide. This publication further discloses that .beta.-pinene will react with sodium bisulfite to form sodium p-menth-1-ene-7-sulfonate (II). The saturated analogs of I and II, i.e., III and IV respectively, have apparently not yet been reported. Little is known concerning the utility of these sulfonated pinene derivatives. U.S. Pat. Nos. 4,224,240 and 4,283,347, however, mention the possible utility of p-menth-1-ene-7-sulfonate salts as detergents and surfactants.
It is an object of the present invention to provide nonpetroleum derived sulfonate salts useful as hydrotropes in aqueous formulations.
It is a further object of this invention to disclose novel menthane sulfonate salts.